This invention relates to electrical circuits and apparatus having inductors or transformers.
In an electrical apparatus, such as an inverter adapted for driving fluorescent lights, one or more input and/or output electromagnetic devices are typically required for matching the electrical apparatus to the input power source, and to the electrical load connected to the output of the apparatus. Such electromagnetic devices are commonly known as inductors, and transformers.
In simple terms, an inductor has a single inductive winding, and is used to compensate for variations in electrical current flow, whereas a transformer has two separate inductive windings located in close proximity to one another and utilizing electromagnetic coupling to provide circuit isolation or changes in voltage.
Typically, a different set of transformers and inductors is needed for each input/output voltage and/or current, or frequency, at which the apparatus will operate. This necessitates carrying an inventory of electromagnetic components of various values to cover the possible combinations of input and output conditions that a given electrical apparatus may encounter in operation, even if the basic electrical apparatus itself, aside from the input/output electromagnetic devices, can be used in a number of different applications. The need to carry this inventory increases the cost of producing and maintaining the electrical apparatus.
What is needed, therefore, is an improved electrical apparatus, having electromagnetic devices which are operable at multiple inductance values.
My invention provides such an improved electrical apparatus through utilization of electromagnetic devices having two or more inductive windings, which may be connected in various series and/or parallel circuit configurations, by inserting them into a circuit board specially configured to accept my improved electromagnetic devices, and attaching jumpers to the circuit board for selecting the particular inductive windings to be incorporated into the electrical apparatus. The windings not selected for a given electromagnetic apparatus remain unconnected within the electrical device.
In one form of my invention, an electrical apparatus comprises an electromagnetic device, a circuit board having an electrical circuit, and one or more jumpers for connecting the electromagnetic device to the electrical circuit. The electromagnetic device has a first and a second winding of common polarity. The electromagnetic device further includes pins electrically connected to the windings and adapted for attachment to a circuit board. The electrical circuit of the circuit board is adapted to receive the pins of the electromagnetic device, and the jumpers are adapted for attachment to the circuit board in a manner connecting the pins of the electromagnetic device to the electrical circuit to alternatively form an electrical connection between the first or second windings and the electrical circuit. The first and second windings of the electromagnetic device are formed from a number of turns of an electrical conductor, and in some forms of my invention the second winding has a different number of turns than the first winding.
In another form of my invention, the electrical apparatus also includes a third winding of common polarity with the first and second windings. The third winding is electrically connected to the pins of the electromagnetic device, and the jumpers are adapted for attachment to the circuit board in a manner connecting the pins of the electromagnetic device to the electrical circuit to alternatively form a series or a parallel electrical connection between the electrical circuit and two or more of the first, second, and third windings. The first, second, and third windings each include a number of turns, and at least one of the first, second, and third windings may have a different number of turns from the others of the first, second, and third windings.
The electromagnetic device may be a transformer with a primary and a secondary winding, with the first, second, and third windings forming a primary winding of the transformer. The first, second, and third windings may each have a different number of turns. The first, second, and third windings may also form the secondary winding of the transformer.
The electromagnetic device may also have more than three windings when constructed as either an inductor or a transformer.
My invention also includes a method for constructing the electrical apparatus in any of the forms described above, and in other forms within the scope of the appended claims.
The foregoing and other features and advantages of my invention will become further apparent from the following detailed description of exemplary embodiments, read in conjunction with the accompanying drawings. The detailed description and drawings are merely illustrative of my invention rather than limiting, the scope of the invention being defined by the appended claims and equivalents thereof.